Hey everyone! I'm new to this DIY solar community and need some advice. I live in the NorCal Bay Area and recently got a Tesla solar setup with two Tesla Powerwall 3 units. With our current solar production hitting around 47 kWh on sunny days, we're finding the 27 kWh capacity of the Powerwalls isn't enough. Right now, we're charging our Tesla EV in the daytime to soak up the excess power since I'm working from home, but that's not a long-term solution. Once I go back to the office, the additional solar generation will go to waste.
So, I'm considering a couple of options:
1. Adding more Tesla Powerwall 3 units, which seems straightforward but costly—around $5k-$7k. Not super excited about getting taken advantage of by installers for a job that seems easy enough to do myself.
2. I've looked into getting cheaper third-party batteries, like a 20 kWh LiFePO4 battery from Taobao. I'm confident I can handle the installation, possibly with a friend's help who's a solar electrician but isn't Tesla certified.
3. Buying another EV to alternate driving and charging between them.
I know Tesla says their systems don't work with non-Tesla batteries, but I'm curious if I could integrate them into my home system. Would a non-Tesla battery discharging be considered solar generation and charging act as home load for the Powerwalls? Also, what happens during power outages? If the Powerwalls are fully charged, will excess energy from the non-Tesla battery cause issues like fires?
If I can set the non-Tesla battery to charge and discharge at specified times, is that a safe option? And lastly, is there any communication between the Powerwalls and non-Tesla batteries regarding AC frequency adjustments, or would that create conflicts? I'd love to hear your thoughts!
4 Answers
Getting excess solar energy into non-Tesla batteries isn’t the challenge—it's figuring out how to efficiently use that energy afterward. If you're tying two different systems together, communication can get tricky, so make sure you're not overlapping outputs. The AC frequency adjustments by the Powerwall are typically one-way; it helps manage solar output but might not directly communicate with other inverters. You've definitely got a handle on some technical aspects, just be prepared for unexpected challenges!
I think your idea about the alternative battery options is smart! The third-party batteries could save you a lot of cash. Just make sure you understand the wiring and potential safety issues before diving in. You're right; Tesla systems are pretty closed off, but if you manage the connection carefully, you should be able to make it work without causing any fires or problems. Just be cautious about the settings if you're sharing loads between the Powerwalls and the non-Tesla batteries!
You could definitely explore charging the EV overnight and letting the solar do its thing during the day when you're not around. Just be mindful of the energy levels in the Powerwalls. You might notice that this helps balance consumption and storage a bit. It’s a practical way to utilize that excess solar without wasting it!
That’s a good point! I can see how that might help balance things out, especially with solar generation issues during the day. Thanks for the tip!
Exactly! Just remember to monitor everything regularly. A DIY approach can be awesome, but you have to stay on top of the system to avoid any issues. Setting specific charge/discharge times should help optimize usage.